Mechanism/regulation of human intestinal thiamin uptake

人体肠道硫胺素摄取的机制/调节

基本信息

批准号：
7270664
负责人：
HAMID M SAID
金额：
$ 27.73万
依托单位：
UNIVERSITY OF CALIFORNIA-IRVINE
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-08-01 至 2009-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7270664
关键词：
Accounting Actins Address Adult Amino Acids Animal Model Antisense RNA Apical C-terminal Caco-2 Cells Cardiovascular system Celiac Disease Cell membrane Cell physiology Cells Chimeric Proteins Clinical Condition Confocal Microscopy Development Disease Elderly Elements Enterocytes Epithelial Epithelial Cells Event Fluorescence Funding Genes Genetic Transcription Growth Homeostasis Human Human Activities Human Cloning Image Impairment In Vitro Individual Intestinal Absorption Intestines Investigation Kidney Diseases Knowledge Laboratories Large Intestine Length Life Luciferases Mammals Mediating Megaloblastic Anemia Membrane Messenger RNA Metabolic Microfilaments Microtubules Molecular Molecular Biology Movement Mus Mutate Mutation N-terminal Nuclear Nucleic Acid Regulatory Sequences Nutritional Organ Donor Patients Physiological Play Principal Investigator Process Proteins Rate Reaction Regulation Regulatory Element Relative (related person)Reporter Reporting Research Personnel Role Sequence Determination Signal Transduction Site-Directed Mutagenesis Small Interfering RNA Source Testing Thiamine Thiamine Deficiency Tissues Transcription Initiation Site Transgenic Mice Transgenic Organisms Tyrosine Vertebral column Vesicle Vitamins Water-Soluble Vitamin Wild Type Mouse Work absorption apical membrane base basolateral membrane brush border membrane day design diabetic in vivo nervous system disorder novel polypeptide problem drinker programs promoter trafficking uptake

项目摘要

DESCRIPTION (provided by applicant): The long-term objective of this renewal application is to continue our investigations into the cellular and molecular mechanisms involved in the absorption of the water-soluble vitamin B1 (thiamin) in the human intestine and their regulation. Thiamin is essential for normal cellular functions and its deficiency (which represents a significant nutritional problem) leads to a variety of clinical abnormalities including cardiovascular and neurological disorders. Humans (and other mammals) cannot synthesize thiamin, and thus, must obtain the vitamin via intestinal absorption. Studies from our laboratory during the current funding period have characterized many aspects of the human intestinal thiamin uptake process including the demonstration that both of the thiamin transporters hTHTR-1 and hTHTR-2 are expressed in the human intestine and play a role in thiamin uptake. These studies have also shown that the hTHTR-1 is expressed at both the apical and basolateral membrane domains of intestinal epithelial cells, while the hTHTR-2 is mainly expressed at the apical membrane domain. In addition, we have cloned and performed initial characterization of the promoters of the genes that encode these transporters (SLC19A2 and SLC19A3, respectively). In new preliminary studies, we found the intestinal thiamin uptake process to be regulated by ontogeny and by dietary thiamin level, and that this regulation appears to involve transcriptional mechanism(s). In other preliminary studies, we have identified two sequences in the hTHTR-1 polypeptide that appear to be important for its targeting to intestinal cell membrane. Our specific aims in this application are: 1) To continue the characterization of the SLC19A2 and SLC19A3 promoters in vitro and in vivo in transgenic mice, 2) To determine the cellular and molecular mechanisms involved in the regulation of the intestinal thiamin uptake process by ontogeny and by dietary substrate levels, and 3) To study the mechanisms involved in membrane targeting and intracellular trafficking of the hTHTR-1 and the hTHTR-2 in human intestinal epithelial cells. Results of these studies should continue to provide novel and valuable information regarding the cellular and molecular mechanisms involved in thiamin uptake by the human intestine and their regulation. This should ultimately assist us in the designing of effective strategies to optimize thiamin body homeostasis in conditions associated with thiamin deficiency and sub-optimal levels.

描述（由申请人提供）：这种更新应用的长期目标是继续我们对人类肠道中水溶性维生素B1（硫胺素）吸收的细胞和分子机制进行研究。硫胺素对于正常的细胞功能及其缺乏症（代表一个重大的营养问题）至关重要，导致多种临床异常，包括心血管和神经系统疾病。人（和其他哺乳动物）无法合成硫胺素，因此必须通过肠道吸收获得维生素。当前资助期间，我们实验室的研究表明，人类肠道硫胺素摄取过程的许多方面，包括证明硫胺素转运蛋白HTHTR-1和HTHTR-2都在人类肠道中表达并在硫胺素摄取中发挥作用。这些研究还表明，HTHTR-1在肠上皮细胞的顶端和基底外侧膜结构域都表达，而HTHTR-2主要在顶端膜结构域表示。此外，我们对编码这些转运蛋白的基因的启动子进行了克隆并进行了初始表征（分别是SLC19A2和SLC19A3）。在新的初步研究中，我们发现肠道硫胺素的摄取过程由个体发育和膳食硫胺素水平调节，并且这种调节似乎涉及转录机制。在其他初步研究中，我们已经确定了HTHTR-1多肽中的两个序列，这些序列对于靶向肠道细胞膜很重要。我们在此应用中的具体目的是：1）继续表征SLC19A2和SLC19A3启动子在体外和转基因小鼠中的体外和体内的表征，2），2），以确定与肠道和饮食级别有关的肠道thiamin摄取过程的调节的细胞和分子机制，以及涉及饮食中的机制，并涉及饮食层次的机制。人类肠上皮细胞中的HTHTR-1和HTHTR-2。这些研究的结果应继续提供有关人类肠道及其调节所涉及的细胞和分子机制的新颖和有价值的信息。最终，这应该有助于我们设计有效的策略，以在与硫胺素缺乏症和亚最佳水平相关的条件下优化硫胺素身体体内平衡。